CHEVY STALLING

1994 Chevrolet Lumina • 140,000 miles

I have an issue with my 94 Chevy Lumina 3.1L 6cyl. Car stalled after a hard start, then I waited and it started up again and it ran ok, engine kinda rough sounding like it wanted to stall. 25 minutes later stalled while driving, couldn't get the engine to turn at all after that. Electrical components worked fine, headlight, electric windows, door locks. Tried jumping and charging battery but acted like it didn't want to keep a charge. Battery is only 13 months old, took to get it checked and its fine. What else could be going wrong? Maybe Alternator or timing belt?